Toxicology USMLE Step 1 Practice Question

A 6-year-old boy presents with lead poisoning from peeling paint exposure. Vital signs: BP 105/68 mmHg, HR 88/min, RR 20/min, temp 37°C, SpO2 98% on room air. Blood lead level is 52 mcg/dL with microcytic anemia (hemoglobin 10.2 g/dL). He exhibits irritability and abdominal discomfort but denies seizures or altered mental status. He takes no chronic medications. Which oral chelation agent is most appropriate for this symptomatic child without encephalopathy?